Sulphonataing process



Patented Feb. 24, 1942 SULLP-HCNATING rnociiss ,L I

Wilhelm Meiser, Munich, Germany, assig'norto General Aniline & Film Corporation, a corpo-, v

ration of Delaware No Drawing. Application August 31,1939, Serial No. 292,889. In Germany September 17, 1938 j 1 1 Claim. (01. 260-}515) The present, invention relates to anew process of sulphonating aromatic carboxylic acid chlorides.

It has been known that by the action of chlorosulphonic acid upon aromatic hydrocarbons the sulpho chlorides are formed and that the quantities of sulpho chlorides obtained are the larger the. larger the employed quantity of chlorosulphonic acid is (Berchte der deutschen Chemischen Gesellschaft, vol. 42, p. 1802). ,In the large scale manufacture of sulpho chlorides of aromatic hydrocarbons chlorosulphonic acid is, therefore, generally employed in a large excess, as far as the sulpho chlorides are not prepared from the sulphonic acids by the reactio with phosphorus chlorides. 1

It has further been known that sulpho chlorides of aromatic carboxylic acids are ob-' tained by the action of chlorosulphonic acid in large excess upon aromatic carboxylic acids; it has also already been proposed to convert an aromatic carboxylic acid chloride into the sulpho chloride of the aromatic carboxylic acid by means of an excess (14 mols) of chlorosulphonic acid (Journ. Chem. Soc., London, 1934,

It was, therefore, surprising and could not be expected, and that is what I have found, that sulphonation products of aromatic carboxylic acids can be obtained in a simple manner by allowing sulphonating agents, which do not form water in the sulphonation process as, for instance sulphuric anhydride or chlorosulphonic acid, to act under sulphonating conditions upon aromatic carboxylic acid chlorides in quantities not exceeding 150% of the theoretically required quantity, and it was also surprising that in this reaction, whether sulphuric anhydride or chlorosulphonic acid are used, mainly the sulpho chlorides of the aromatic carboxylicacids are aqueous medium, in which operation inheres the danger of a saponification of the sulpho chlorides; and when the sulpho chlorides shall be worked up in the absence of water a bothersome drying process becomes necessary. The

' new process in contradistinction thereto yields products which can be employed without puri'-.

fication for further reactions thus, for instance, they can be condensed with amino or hydroxy compounds in the presence of the tertiary base.

My new process is carried out as follows: Sulphuric anhydride or chlorosulphonic acid are added, if necessary under cooling, to the aromatic carboxylic acid chloride, if desired in the presence of an indifierent solvent, and the mixture is allowed to react at sulphonating temperature.

The sulphonating temperature required depends,

As it could be expected, the sulphonation according to the new processtakes place at about the same temperatures as the known'sulphonation of armoatic carboxylic acids with chlorosul phonic acid.

The following examples illustrate the invention without, however, restricting it thereto the parts being by weight.

Example 1 Into parts of benzoyl chloride arepassed at C. SOs-vapors until the increase in weight amounts to 71.3 parts. Thereupon the temperature is raised to C. and kept for 2 hours. There is obtained a viscous product ,fiowing when warmed which mainly consists of benzoic acid-3-sulpho chloride and which can be used for the condensation with compounds containing hydroxyl and/or amino groups.

' In, order to isolate the benzoic acid-3-sulpho chloride the reaction mass is dissolved in chloroform solution, washed with ice water, the washing water is removed and the chloroform solution is dried with calcium chloride. After distilling off the solvent in vacuo the residue is recrystallized from toluene; melting point 133 C. The product thus obtained is identical with henzoic acid-B-sulpho chloride obtained from benzoic acid with the large excess of chlorosulphonic acid.

' Example 2 Example Into 110 parts of o-toluic acid chloride are passed at 110 C. SOs-vapors until the increase in weight amounts to 63 parts. Thereupon the.

140.5 parts of benzoyl chloride andparts of' temperature is raised to 130 C. and kept for 2 hours. The reaction product obtained shows similar properties as the product of Example 1 and consists mainly of o-toluic acid sulpho chloride of the melting point 152 C. and is identical with the o-toluic acid sulpho chloride obtained from o-toluic acid with a large excess of chlorosulphonic acid.

'- Example 4 Into 125 parts of p-chlorobenzoyl chloride are) passed at 110 C. 61 parts of SOs-vapors; the temperature raised during 3 hours 45 minutes to 160 C. and the mixture kept at this temperature for 1 hour 45 minutes. The reaction product obtained shows similar properties as the product of Example 1. From the reaction mass the p-chlorobenzoic acid sulpho chloride can be isolated which melts when recrystallized from toluene at 153 C.

Example 5 -the theoretically required quantity.

WILHELM MEISER. 

